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ready to epoxy door halves - anyone add additional mating surfaces?

I'm about the epoxy the inner and outer door shells together. Given all the discussions on door flexing, especially near the bottom of the door, has anyone added any additional structural elements to further help the structural integrity of the doors? There is some open space below the window and near the bottom edge.

Pics would be appreciated if anyone has done this.
 
My opinion extra at the bottom is not required. The pins makes the structure very rigid when shut. When the door is open (or simply not locked) the door is very fragile, not because of the door itself, because the hinges will snap like a pretzel if you let a good gust of wind get hold of it (or as in my case a prop blast from a C-130).

The door went flying over the top of the fuselage and landing on the side of the ramp in the grass, but not damaged. Replacement hinges came from Van’s the next day and I flew home.

The rule became “if not in the hangar, and if no one is getting in or out of the plane, the doors are always shut and locked, no exceptions”.
Carl
 
The door went flying over the top of the fuselage and landing on the side of the ramp in the grass, but not damaged. Replacement hinges came from Van’s the next day and I flew home.

Curious since you report 'not damaged', where the hinge failed, as well as where the gas strut/attachment failed?
 
The hinges just broke at the eyelets. Each hinge half was fine - the hinge screws did not pull out of the door. The strut rivets pulled out of the door. I fixed that after I got home.

Carl
 
I filled the door cavities with expanding pour foam. Stiffens up the doors significantly. Note: not the stuff you that is used for sealing doors and windows that comes in a can. Use 4 or 6 pound stuff used for boat building. Bonded door halves first, then after cure drilled some well placed 1/4” holes on the inside shell, mixed fast and injected with a big livestock syringe. Hole’s at top allow excess foam to escape as it expands. When cured I just trimmed and plugged the holes with flox.
 
I filled the door cavities with expanding pour foam. Stiffens up the doors significantly. Note: not the stuff you that is used for sealing doors and windows that comes in a can. Use 4 or 6 pound stuff used for boat building. Bonded door halves first, then after cure drilled some well placed 1/4” holes on the inside shell, mixed fast and injected with a big livestock syringe. Hole’s at top allow excess foam to escape as it expands. When cured I just trimmed and plugged the holes with flox.

David,

How did you ensure the expanding pour foam wouldn't restrict/come in contact with the door latch linkages inside the door ?
 
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I epoxied in an approx 6” x12” rectangle of 1” divinicell behind the elbow pocket.
Prob weighs 100g extra per door.
Given I have the planearound center latch it’s probably overkill but it was pretty straight forward.
Don’t think I have any pics. I’ll look.
 
David,

How did you ensure the expanding pour foam wouldn't restrict/come in contact with the door latch linkages inside the door ?

Taped off what I could with good HVAC aluminum tape and just used some tools to pick out and scrape the cavity needed for the latching mechanism.
 
Airward Kit for Hinges

I wouldn't add the weight of foam into the doors. I've seen an RV-10 where the doors were injected with foam. The doors were so heavy they required heavy duty struts to lift them and they went up rather slowly. That made the decision for me - no foam, just a good strong bond of the two halves.

I agree with Carl that the week point seems to be at the hinges. If you want to strengthen them, a company called AirWard sells a Main Door Hinge Reinforcement Kit for the RV-10, to strengthen the hinges and prevent the doors from separating. That's what I have for my RV-10, although I haven't installed the kit yet.
 
I'm about the epoxy the inner and outer door shells together. Given all the discussions on door flexing, especially near the bottom of the door, has anyone added any additional structural elements to further help the structural integrity of the doors? There is some open space below the window and near the bottom edge.

Pics would be appreciated if anyone has done this.

I'd like to make a recommendation. If I were to do this all over again, I would add a couple of layers of carbon fiber on the inside of the upper part of the door halves before epoxying them together. I've been so impressed with the carbon fiber I've used that I think it would negate the twisting motion that is present in most installations. This would be so easy to do and there are no drawbacks.
 
I wouldn't add the weight of foam into the doors. I've seen an RV-10 where the doors were injected with foam. The doors were so heavy they required heavy duty struts to lift them and they went up rather slowly. That made the decision for me - no foam, just a good strong bond of the two halves.

I agree with Carl that the week point seems to be at the hinges. If you want to strengthen them, a company called AirWard sells a Main Door Hinge Reinforcement Kit for the RV-10, to strengthen the hinges and prevent the doors from separating. That's what I have for my RV-10, although I haven't installed the kit yet.

Your joking about the weight I hope. If not, you have no idea what kind of foam I am talking about.
 
I'd like to make a recommendation. If I were to do this all over again, I would add a couple of layers of carbon fiber on the inside of the upper part of the door halves before epoxying them together. I've been so impressed with the carbon fiber I've used that I think it would negate the twisting motion that is present in most installations. This would be so easy to do and there are no drawbacks.

Jeff -most of what I've read is concern about the lower portion of the doors flexing and the concern about pins possibly pulling out (perhaps completely addressed with the PlaneAround 180 latch). Why would you add support to the top half of the door and can you explain more about the twisting motion that you mentioned ?
 
Jeff -most of what I've read is concern about the lower portion of the doors flexing and the concern about pins possibly pulling out (perhaps completely addressed with the PlaneAround 180 latch). Why would you add support to the top half of the door and can you explain more about the twisting motion that you mentioned ?

It is the upper part of the door that is a bit lacking in rigidity and can twist a bit, eventhough the effect is seen in the lower half. The lower half is quite strong. I think the window area, with it's limited box structure area, is where the flexing is coming from. I did nothing out of the ordinary to add support and have had no issues due to lack of rigidity in the upper half. I suspect symptoms could be worse if care is not taken with alignment in the latching system or too strong of a damper is used.

Larry
 
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Your joking about the weight I hope. If not, you have no idea what kind of foam I am talking about.

David,

I can only speak about the doors I saw and I'm not sure what foam type they used. However, 5 to 6 lb foam weighs 5 to 6 lbs per cubic foot. What's the volume of a door cavity? 0.333 cf, 0.5 cf, 0.666 cf....?
 
David,

I can only speak about the doors I saw and I'm not sure what foam type they used. However, 5 to 6 lb foam weighs 5 to 6 lbs per cubic foot. What's the volume of a door cavity? 0.333 cf, 0.5 cf, 0.666 cf....?

I ended up mixing 10 oz in 2 oz batches to fill each door. I used 2 pound fill but would like 4 pound for better density. At least half of that never got in the doors. I “guesstimate” about 250 cubic inches. Maybe what you saw was window/door spray can foam which is denser and does not expand or harden like the boat stuff. We used pour foam during the Cozy MKIV build in a few spaces, and also used it to rebuild the nose due to a nose strut failure. It was a general rule to never use the spray can stuff.
The factory door struts are a known week link on the RV-10 doors. Some builders opt for an stiffer strut. I used the factory struts and they showed no signs of weakening the 3 years until I sold it. I had planned to replace them with the stiffer versions if I ever needed to replace them. The bottom door latch adds a little weight at the bottom, wether using the center cam or the ugly latch from Vans. The Van’s hinges are kinda crude but they work fine. I never felt real good about the pop riveted strut brackets. Doing it again I would embed a steel or aluminum plate and use screws for mounting the brackets.
 
I have the PlaneAround latch mechanism installed and the supports epoxied in. When I put the outer door shell on to see how it fits I noticed a slight outward bump where the latching mechanism is hitting the outer door shell. Is this normal? How much will the ParaBeam on the elbow cavity raise the contact point to the outer door shell ? See attached pic (sorry about the pic rotation). The small aluminum shroud piece above the gearbox is to deflect any epoxy awy from the gear box that might drip during the epoxy process (Stole this idea from Adrian)

Second question - In the Van's instructions they say to use the ParaBeam on the elbow and cranial cavity parts of the door. There is one smaller section ( not sure what it is called and it is not identified in the Van's instructions ) that is forward of the elbow cavity and above the latch pocket area. See attached pdf figure. Is this area supposed to be epoxied and should you use the ParaBeam ? The height of this feature is not as tall as the elbow cavity feature so more epoxy/ParaBeam would be needed to mate the two door shells.
 

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Jeff -most of what I've read is concern about the lower portion of the doors flexing and the concern about pins possibly pulling out (perhaps completely addressed with the PlaneAround 180 latch). Why would you add support to the top half of the door and can you explain more about the twisting motion that you mentioned ?

It's true the twisting motion/flexing is what led to the possibility of the original stock doors from being closed when the handle is closed. I'm addressing a similar situation. My friend who built his 10 put a bunch of carbon fiber on the outside top portion of the door. I was impressed and had never seen a door that rigid. If you were to place one hand on the bottom left of the door and another on the bottom right, you can flex the door in and out. The carbon would alleviate this.

Hence, If someone were to sandwich 4 layers of carbon between the inner and outer shells, the carbon fiber would be internal and not interfere with the installation of the planearound latching system. That's what I'd do! It would take so little effort, would only add a few ounces, and stiffen the door up.
 
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Second question - In the Van's instructions they say to use the ParaBeam on the elbow and cranial cavity parts of the door. There is one smaller section ( not sure what it is called and it is not identified in the Van's instructions ) that is forward of the elbow cavity and above the latch pocket area. See attached pdf figure. Is this area supposed to be epoxied and should you use the ParaBeam ? The height of this feature is not as tall as the elbow cavity feature so more epoxy/ParaBeam would be needed to mate the two door shells.

Has this question been answered anywhere? After lots of searching I can’t seem to find an answer. What did everyone for the non-identified cavity and the latch pocket cavity? Did you apply parabeam? Just apply thickened epoxy? Some other application process?

Thanks,
Zach
 
Has this question been answered anywhere? After lots of searching I can’t seem to find an answer. What did everyone for the non-identified cavity and the latch pocket cavity? Did you apply parabeam? Just apply thickened epoxy? Some other application process?

Thanks,
Zach

I just followed the plans. I don't have any opinion on the non-identified cavity but if you were to put par abeam on the latch pocket it would be too thick as that cavity is at the same height as the outer flange.
 
Jeff -most of what I've read is concern about the lower portion of the doors flexing and the concern about pins possibly pulling out (perhaps completely addressed with the PlaneAround 180 latch). Why would you add support to the top half of the door and can you explain more about the twisting motion that you mentioned ?

AFAIK all of the in flight door failures were due to them being ‘closed’ with the front pin engaged but the aft pin outside the fuselage. This is ‘encouraged’ by the forward placement of the door handle, and the flexibility of the doors. Once moving at high speed the bottom of the door can move aft, pulling out the front pin, …. The Plane around latch, where the doorsill rotating latch pulls the door inward before extending the pins, makes this hard to happen (I won’t say impossible, because some fool can always defeat a foolproof thing).
 
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